A multitude of different, multimedia services have been developed using packet-switched communication over IP (Internet Protocol). Multimedia services typically involve the transmission of media in different formats and combinations over IP networks. A network architecture called IMS (IP Multimedia Subsystem) has been developed by the 3rd Generation Partnership Project (3GPP) as a platform for handling and controlling multimedia services and sessions, commonly referred to as the IMS network. Terminal users connected to various access networks, including fixed and mobile networks, can thus be served by the IMS network to invoke and consume multimedia services. The services that can be implemented by using IMS may involve file transfers, media downloads, and conversational sessions such as MMTel (Multimedia Telephony) and PoC (Push-to-talk over Cellular). However, the present invention is not limited to services enabled by IMS.
Operators of access networks typically monitor the performance of their networks with respect to various characteristics and aspects, in order to find any performance-related shortcomings and to configure different elements and parameters in the network impacting the network performance. Network performance is monitored also to ensure that various obligations towards subscribers and content providers are met, such as service level agreements and that expected levels of QoS (Quality of Service) are fulfilled. Various sensors and counters can be installed in different network nodes in order to collect measurements of predefine performance-related parameters during operation of the network. In this context, a performance-related parameter is often referred to as “KPI” (Key Performance Indicator) being an indication of the service quality basically as perceived by the service user. Data throughput and latency are typical examples of such performance-related parameters or KPIs.
A policy control node is typically used by the access network, responsible for authorisation and admission of communication sessions for terminals in the network, based on various predefined policies and rules. According to 3GPP, the policy control node operates according to a function called PCRF (Policy and Charging Rule Function), sometimes alternatively referred to as PDF (Policy Decision Function).
Predefined session admission rules thus specify when to allow sessions for specific users and/or services. Such rules and other parameters can be combined into policies valid for specific users or services, or both, to form subscription profiles. These subscription profiles are stored in a database called SPR (Subscription Profile Repository) residing in the policy control node or PCRF. When a session request for a certain service is received from a terminal user, a policy relevant to that user and service is thus applied for allowing or rejecting the session request, and also for setting appropriate communication parameters and reserving network resources.
Many services in communication networks require a certain QoS (Quality of Service) in order to provide an adequate and expected result to users consuming the services. Per UMTS (Universal Mobile Telecommunications System) networks, different traffic classes have been defined to cater for various quality requirements, e.g. regarding hit rates and delays, when reserving network, resources for a requested service. These traffic classes include “conversational”, “streaming”, “interactive” and “background”, being applied to services basically sensitive to transfer delays in different ways. For example, services of the conversational class tolerate only small delays, also referred to as “real-time”, whereas the background class is applied to the least delay-sensitive services, also referred to as “best effort”.
Another aspect that typically dictates the QoS requirements for a session is the subscription type. Thus, subscribers may be offered specific subscription types with different levels of service quality. For example, using current terminology, a “Platinum” subscription may be defined with a relatively high service level, whereas “Gold”, “Silver” and “Bronze” subscriptions may provide successively lower service levels. Moreover, specific services may also be offered with different service levels, e.g. at different prices and/or depending on the time of day, week or season.
In this description, the term “service level” is used to generally represent the level of service quality in any respect as perceived by a user when consuming a service, sometimes also referred to as “QoE” (Quality of Experience). An alternative term for service level could be “quality level” in this description. Factors that could impact the service level in the context of this description may include, without limitation: service availability, media quality, session set-up latency, media latency, data throughput, bandwidth, error rate, service reliability, and so forth. Effectively, the appropriate service level is implemented for a session when roles in the user's subscription profile are enforced in the network.
FIG. 1 illustrates how a media session is established for a user of a mobile terminal A, according to the prior art. Terminal A is connected to a mobile access network in which a network gateway GGSN (Gateway GPRS Support Node) 100 is generally responsible for reserving media transport resources in the access network for media sessions.
Briefly described, terminal A requests a service involving media communication with an opposite party B, in a first step 1:1, from an application in an IMS network, here represented by an IMS core 102. In a next step 1:2, authorisation of the requested service is generally made by a policy control node 104 associated with the mobile network. Further, the subscription profile of the user is fetched from an SPR 106, as shown by a step 1:3. Rules in the subscription profile dictating the service level, are also enforced in GGSN 100, in a further step 1:4, to reserve network resources and set communication parameters for the forthcoming media session. The media session with party B can now be conducted as shown by a step 1:5. When the session is completed, a charging data record “CDR” is finally sent in a step 1:6 from GGSN 100 to a charging system 108 responsible for billing the user in due course.
The service quality provided to a user may thus be highly dependent on terms in the user's subscription, i.e. the parameters and QoS attributes being defined as rules in the subscription profile. In particular, the QoS attributes effectively impact the resulting KPIs if measured during service usage. For example, a bronze user consuming a streaming service could be allowed a streaming session with a maximum throughput of 64 kbps (kilobits per second), while a platinum user may be guaranteed a minimum throughput of 128 kbps for the same streaming session.
When requesting a specific service involving media communication, a user is first provisioned by the policy control node based on the user's subscription profile, as described above, before a media session can be established accordingly. The various terms for service usage on a session basis are thus dictated by the rules in the user's subscription profile determining the due service level. These rules may also be evaluated with respect to a detected “context” of the user including the present environment or situation such that different rules are valid in different circumstances. Mechanisms are available for detecting the current context of the user in terms of various context parameters and aspects, which are not necessary to describe further to understand the following description.
Thus, services can be provided to different users with differentiated service levels, e.g. for platinum, gold, silver and bronze users, by setting parameters and QoS attributes, i.e. rules, in their subscription profiles. The terms defined in the subscription profile are thus more or less static, basically as agreed by the operator and the user, and any service level differentiation is determined by the agreed subscription profiles.
However, a more flexible differentiation of service levels would be desirable since users having basically the same subscription, at least with respect to one or more particular services, may behave somewhat differently in terms of service usage and their payment of bills. In the solutions available today, all users having established the same subscription terms or rules for consuming a particular service, will automatically obtain the same service level. It is thus a problem that it is not easy to provide different service levels for users having the same subscription terms, e.g. to encourage or promote certain users.
It may be desirable for network operators and service providers to give better terms for users deemed more “important” than others, for various reasons, or to stimulate the usage of specific services, and so forth. For example, two users A and B have the same subscription terms X of a service Y, providing for a certain service level. User A consumes the service Y much more frequently than user B does, without interrupting the service and without complaining to the operator, also paying the bills in due time. On the other hand, user B consumes the service Y only very occasionally and is not inclined to use other services being offered to him/her, and so forth.
In the situation above, users A and B receives the same service level when consuming service Y, as dictated by subscription terms X. However, from the perspective of the network operator or service provider, user A is deemed more “valuable” than user B and has a greater potential for increasing the usage of services offered. According to the solutions available today, the only way to generally stimulate increased service usage is to offer new subscription terms to selected users, which requires manual efforts to identify those users and negotiate with them.